An apparatus for heat shrinking a package may be used to heat shrink a package. This process may be performed in the context or packaging foods such as meat and cheese. The food can be packaged in a heat shrinkable material. The material is shrunk around the food in the apparatus, which may be called a shrink tunnel or shrink tank. The purpose or the shrinking is to properly seal the package and to improve its appearance.
Such an apparatus may involve hot air being applied to the package, causing the material to shrink around the food. A problem with this method is that when packaging cold food products, shrinking stops once the material contacts the cold food. Such incomplete shrinking processes can result in a package which may not be sealed properly and/or which is aesthetically displeasing. In other such apparatuses, the package is subjected to immersion in a water bath or passage through a water curtain. The application of water can at least partly overcome the problem of the material stopping shrinking when coming into contact with a cold food product. However, immersion in water requires a large amount of energy, particularly in the initial stages of using the apparatus when the wafer must be heated to a high temperature (the water must also be subsequently maintained at a high temperature).
U.S. Pat. No. 5,400,570 discloses a method of heat shrinking a package in which both hot air and hot water are applied to the package. The hot air, which is at a higher temperature than the hot water, is used to heat the water. Meanwhile, US 2009/0071107 A1 discloses a system in which steam is extracted from the apparatus so as to re-circulate its heat. However, such apparatuses require a relatively large amount of energy, particularly during the start-up phase or use of the apparatus.
An aim of the present invention is to provide an apparatus liar heat shrinking a package. Another aim is to provide a method for heat shrinking a package.